Skip to tutorial content
Rate module Not yet rated

Reconciliation and Data Source Precedence

4 min read
On this page

In this lesson, you will learn:

  • What reconciliation rules do
  • What data source precedence means
  • SNWR’s field ownership

🔁 Quick look back: Last time: Discovery Source and Data Sources. You learned how every CI records which source reported it.

1 The Problem: Two Sources Overwrite Each Other

Priya sets a server’s support group by hand. That night, another source writes a different value. Next day, Priya fixes it again. So:

  • Fields flip back and forth.
  • Nobody trusts the value.

🎯 The problem: Two sources keep overwriting each other.

👉 The fix: Use reconciliation rules to say which source owns each field.

Table of fields and which source owns them.
Figure 1. Who owns which fields on SNWR’s server CIs.

2 Reconciliation in plain words

Key term: Reconciliation rule

Says which sources may update which fields of a class.

Key term: Data source precedence

When several sources may update a field, which one wins. A lower number usually means higher priority.

Key term: Data refresh rule

Stops a source from updating a field if another source reported it recently.

⭐ Remember: Give each field one clear owner. Shared fields cause flip-flopping.

3 Common patterns

  • Discovery owns technical fields it can see.
  • People own business fields: owners, support groups, cost centres.
  • Imports get the lowest priority, or are switched off.

4 Project Clear View: How We Implemented It

📍 Situation: Hana wants to protect the fields her team sets by hand.

🧭 Decision: Agree field ownership now, and build rules from it in design.

🛠️ Steps we took:

  1. Listed the fields on server CIs that matter to SNWR.
  2. Gave each field one owner: Discovery or people.
  3. Set the spreadsheet import to lowest priority until it’s switched off.
  4. Recorded the table for design.

✅ What we verified:

  • Hana and Priya agreed who owns each field.
  • No field has two owners.

📁 Evidence: Field ownership table, used for DD-D05 (see Solution Design › Designing CMDB and Identification Decisions).

5 Quick recap

  • Reconciliation rules say which source may update which fields.
  • Data source precedence decides who wins when several may update.
  • Give each field one owner.
  • At SNWR, Discovery owns technical fields and people own business fields.

6 Check yourself

Think of your answer first. Then tap to check.

1 What does a reconciliation rule do? Show answer

It says which sources may update which fields of a class.

2 Who owns the support group field at SNWR? Show answer

People (Priya’s team), not Discovery.

3 What’s a data refresh rule for? Show answer

It stops a source updating a field another source reported recently.

Nice work! SNWR’s fields each have one owner. 🎉
Next up: CI Reclassification

Was this lesson helpful?

Have a question or doubt?

Ask here and get help from instructors and fellow learners.

0 / 300

Only logged-in learners can post.